JP3437200B2 - Color inkjet recording method - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color ink jet recording method capable of recording a color image clearly and with high density. More specifically, it is specifically related to yellow (Y), magenta (M), cyan (C), or green ( The present invention relates to a color inkjet recording method using color inks such as G), red (R), and blue (B), and black (Bk) ink.

The present invention is applicable to paper, cloth, non-woven fabric, and OHP.
It can be applied to all devices that use a recording medium such as paper, and specific applicable devices include a printer, a copying machine, and a facsimile.

[0003]

2. Description of the Related Art Ink jet recording methods are used in printers, copying machines, facsimiles, etc. because of their low noise, low running cost, easy miniaturization of devices, and easy colorization.

In general, a color ink jet recording method uses three color inks of cyan, magenta and yellow, and further, four color inks including black are used for color recording.

In the conventional ink jet recording method, it was necessary to use a special paper having an ink absorbing layer in order to obtain a color image of high color development without ink bleeding. A method that has a printability on "plain paper" that is used in large quantities in copying machines and the like has also been put into practical use.

[0006]

The inks used in conventional ink jet recording generally contain water as a main component and a water-soluble high-boiling solvent such as glycol for the purpose of preventing drying and clogging. It is common. When recording on plain paper with such ink, the ink penetrates inside the recording paper and a sufficient image density cannot be obtained, or the filler and sizing agent on the recording paper surface are unevenly distributed. The unevenness of the image density, which is considered to be caused by the above, occurred. Also, especially when trying to obtain a color image,
Since the inks of multiple colors are layered one after the other before they are fixed, at the boundary of different color images, the colors are bleeding or unevenly mixed (hereinafter referred to as bleeding), and a sufficiently satisfactory image is obtained. There wasn't.

As means for solving the above-mentioned problems, Japanese Patent Laid-Open No.
Using an ink containing a compound that enhances permeability such as a surfactant in the ink disclosed in JP-A-5-65269,
Further, JP-A-55-66976 discloses the use of an ink mainly composed of a volatile solvent. However, in the former method, the penetrability of the ink into the recording paper is improved, and although bleeding can be suppressed to some extent, the ink penetrates deeply into the recording paper together with the colorant, resulting in a decrease in image density or a clear image. There was an inconvenience such as deterioration of the property. Further, since the wettability with respect to the surface of the recording paper is improved, the ink is likely to spread, resulting in a decrease in resolution and bleeding, which is unfavorable because the quality is deteriorated particularly when expressing black characters.
On the other hand, in the case of the latter, in addition to the disadvantage of the former, clogging due to evaporation of the solvent in the nozzle portion of the recording head is likely to occur, which is not preferable.

Further, the following recording methods have been proposed in order to prevent bleeding of ink between black and color colors and to improve color recording quality by achieving both black printing quality.

Japanese Unexamined Patent Publication (Kokai) No. 3-146355 proposes a method of not recording an area along the boundary area between black and color. However, this method has a drawback that bleeding between black and color can be suppressed to some extent, but recorded data changes.

Further, in Japanese Patent Laid-Open No. 4-158049, a multicolor head for color recording and a head for character recording are provided, and the multicolor head and the character recording head are switched based on a recorded image. A method of recording is proposed. However, this method has a drawback in that it has an unavoidable increase in cost and an increase in size of the apparatus because it has a character recording head in addition to a conventional multi-color head for color recording.

Further, Japanese Patent Application Laid-Open No. 4-147866 proposes a recording method in which the fixing time of the color ink is set shorter than the fixing time of the black ink and the fixing time of the color ink is set to a predetermined time or less. But with this method,
Unfixed black ink flows into the previously fixed color ink and bleeding between black and color deteriorates, and a satisfactory image cannot be obtained.

The present invention has been made to solve the above-mentioned problems of the prior art, and its object is to record an independent black image area which does not come into contact with a color image area. In addition to high density and excellent character quality, in other areas, an excellent color image with no ink bleeding between each color of black and color can be obtained, that is, high quality black recording and high quality. The present invention provides a recording method that can realize both excellent color recording and can downsize the apparatus.

[0013]

The present invention is directed to a black ink,
In a color inkjet recording method of forming a desired color image on a recording medium by ejecting a plurality of color inks different from the black ink onto the recording medium, the bleeding rate of the black ink represented by the following general formula (I) Is smaller than the bleeding rate of the color ink.

(I) A = B / C A: Bleeding rate B: Diameter (μm) of single dot formed on high-quality paper C: Diameter of ejected single ink droplet (μm)

Further, it is judged whether or not there is a color image area adjacent to the black image area, and according to the judgment result,
It is characterized in that it is determined whether the black image area is formed by the black ink or the color inks of a plurality of colors.

Further, the bleeding rate of the black ink is 1.2 to
It is in the range of 2.5 and the bleeding rate of the color ink is 1.8.
It is characterized by being in the range of up to 3.5.

Further, the fixing time of the black ink is longer than the fixing time of the color ink.

[0018]

In order to prevent the bleeding between inks, it is necessary to improve the wettability of the ink to the recording medium as a recording medium and increase the bleeding rate. However, if the bleeding rate is too large, the shape of the recording dots becomes irregular, and the character quality is particularly degraded. Therefore, it is possible to improve the quality of black characters by making the bleeding rate of black ink smaller than that of color ink.

Further, since the color ink having a large bleeding rate is quickly fixed, when the color ink comes into contact with the black ink, the black ink flows into the color ink fixing surface,
The bleeding between black and color gets worse. In order to prevent this, when a color image area exists adjacent to the black image area of the print data, the black image is formed by a plurality of color inks, whereby the inflow of the black ink can be prevented. On the other hand, when a color image does not exist adjacent to the black image area, high quality black characters can be realized by forming with black ink.

When the bleeding rate of the black ink is less than 1.2, the spread of the ink droplets is small, and when recording a solid black image, it is necessary to increase the amount of ink shot in, and the absorption of the recording paper. The capacity may be exceeded. When the bleeding rate of black ink exceeds 2.5, the ink droplets spread too much and the sharpness of the edge of the dot disappears, resulting in poor print quality.

When the bleeding ratio of the color ink is less than 1.8, the bleeding between the colors is deteriorated, and when the bleeding ratio is more than 3.5, the ink droplets spread too much and the density is lowered.

[0022]

First, an outline of an embodiment of the present invention will be described.

The inventors of the present invention have made earnest studies to realize high-quality black character quality and color recording without bleeding on plain paper. As a result, the bleeding rate of black ink as the ink to be used is better than the bleeding rate of color ink. It is small, and it is further determined whether or not there is a color image area adjacent to the black image area of the print data, and according to the determined result,
It has been found that both high-quality black recording and high-quality color recording can be realized by using the method of forming the black image area with the black ink or the color ink of a plurality of colors.

That is, in order to prevent bleeding between the inks, it is necessary to improve the wettability of the ink with respect to the recording medium as a recording medium and increase the bleeding rate. However, if the bleeding rate is too large, the shape of the recording dots becomes irregular, and the character quality is particularly degraded. Therefore, it is possible to improve the quality of black characters by making the bleeding rate of black ink smaller than that of color ink.

Further, since the color ink having a large bleeding rate is quickly fixed, when the color ink comes into contact with the black ink, the black ink flows into the color ink fixing surface,
The bleeding between black and color gets worse. In order to prevent this, when a color image area exists adjacent to the black image area of the print data, the black image is formed by a plurality of color inks, whereby the inflow of the black ink can be prevented. On the other hand, when a color image does not exist adjacent to the black image area, high quality black characters can be realized by forming with black ink.

In the present invention, the bleeding rate is adjusted by adding a surfactant and a penetrating solvent to the ink.

Examples of the surfactant include anionic surfactants such as fatty acid salts, higher alcohol sulfate ester salts, alkylbenzene sulfonates and higher alcohol phosphate ester salts, and cations such as aliphatic amine salts and quaternary ammonium salts. Surfactant, higher alcohol ethylene oxide adduct, alkylphenol ethylene oxide adduct, aliphatic ethylene oxide adduct, polyhydric alcohol fatty acid ester ethylene oxide adduct, higher alkylamine ethylene oxide adduct, fatty acid amide ethylene oxide adduct, polypropylene Nonionic surfactants such as glycol ethylene oxide adducts, fatty acid esters of polyhydric alcohols, fatty acid amides of alkanolamines, amino acid-type and betaine-type amphoteric surfactants, etc. are used. That. There is no particular limitation, but more preferably, a nonionic surfactant such as ethylene oxide adduct of higher alcohol, ethylene oxide adduct of alkylphenol, ethylene oxide-propylene oxide copolymer, ethylene oxide adduct of acetylene glycol, etc. To use. Further, the addition mole number of the ethylene oxide adduct is particularly preferably in the range of 4 to 20.

The amount of surfactant added is not particularly limited, but is preferably in the range of 0.01 to 10%. If it is less than 0.01%, the bleeding rate generally does not increase, although it depends on the kind of the surfactant. If it exceeds 10%, the initial viscosity of the ink becomes large.

As the solvent for imparting permeability, ethers such as tetrahydrofuran and dioxane, lower alkyl ethers of polyhydric alcohols such as ethylene glycol methyl ether, diethylene glycol monomethyl ether and triethylene glycol monomethyl ether, ethanol and isopropyl. Alcohol and the like are preferably used.

The amount of the solvent added is not particularly limited, but is preferably in the range of 0.1 to 20%. If it is less than 0.1%, the desired bleeding rate generally does not increase, although it depends on the kind of the solvent. If it exceeds 20%, the solubility of the colorant is slightly lowered, which is not preferable.

As the dye used in the recording ink, almost all of the water-soluble acid dyes, direct dyes, basic dyes and reactive dyes described in the color index (COLOR INDEX) can be used. Further, even those not described in the color index can be used as long as they are water-soluble dyes. The amount of the dye used is not particularly limited, but 0.1% by weight to 2% with respect to the total weight of the ink.
A range of 0% by weight is preferred.

In addition to the above additives, the recording ink usually contains water and, if necessary, a water-soluble organic solvent. The water-soluble organic solvent, dimethylformamide, amides such as dimethylacetamide, ketones such as acetone, polyethylene glycol, polyalkylene glycols such as polypropylene glycol, ethylene glycol, propylene glycol, butylene glycol, triethylene glycol, 1, 2,6-hexanetriol, thiodiglycol, hexylene glycol,
Alkylene glycols such as diethylene glycol, lower alkyl ethers of polyhydric alcohols such as ethylene glycol methyl ether, diethylene glycol monomethyl ether and triethylene glycol monomethyl ether, monohydric alcohols such as ethanol and isopropyl alcohol, glycerin and N-methyl -2-
Pyrrolidone, 1,3-dimethyl-2-imidazolidinone, triethanolamine, sulfolane, dimethyl sulfoxide and the like are used. The content of the water-soluble organic solvent is not particularly limited, but is preferably 1 to 80% by weight.

In addition, if necessary, a viscosity adjusting agent, pH
Additives such as regulators, preservatives, antioxidants and evaporation promoters may be added.

The ejection amount of the ink used in the present invention depends on the recording density, but as a single droplet, black ink is 10 to 300 pl and color ink is 5 to 100 pl.
The range of is preferable. If the black ink is less than 10 pl and the color ink is less than 5 pl, sufficient recording density cannot be obtained, and if the black ink is more than 300 pl and the color ink is more than 100 pl, the absorption capacity of the recording paper may be exceeded.

In the present invention, the bleeding rate of the black ink needs to be smaller than the bleeding rate of the color inks, but the bleeding rate of the ink is preferably in the following range.

Black ink bleeding ratio 1.2 to 2.5 Color ink bleeding rate 1.8 to 3.5

When the bleeding rate of the black ink is less than 1.2, the spread of ink droplets is small, and when recording a solid black image, it is necessary to increase the amount of ejected ink and the absorption of the recording paper. The capacity may be exceeded. When the bleeding rate of black ink exceeds 2.5, the ink droplets spread too much and the sharpness of the edge of the dot disappears, resulting in poor print quality.

When the bleeding ratio of the color ink is less than 1.8, the bleeding between the colors is deteriorated, which is not preferable, and when the bleeding ratio is more than 3.5, the ink droplets spread too much and the density is lowered. To do.

The bleeding rate is adjusted by adjusting the amount of the surfactant or penetrating solvent added as described above. However, if necessary, it may be adjusted by adjusting the physical properties such as the amount of solvent, surface tension and viscosity. It is possible.

Next, the recording method of this embodiment will be described in detail with reference to the drawings.

FIG. 1 shows a perspective view of a recording apparatus for carrying out the ink jet recording method of the present invention.

The carriage 101 is equipped with a print head 102 and a cartridge guide 103, and guide shafts 104 and 10 are provided.
5 can be scanned. The recording paper 106 is the paper feed roller 1
The paper feed roller 10 is fed into the main body apparatus by 07.
8 and a pinch roller (not shown) and a paper pressing plate 109 sandwiches the paper 8 and the paper is fed to the front of the paper feed roller 108 for printing. Two types of ink cartridges, a color ink cartridge 110 that stores three colors of yellow, magenta, and cyan, and a black ink cartridge 111, are separately inserted into the cartridge 103.
Communicate with 2.

As the yellow, magenta, and cyan inks stored in the color ink cartridge 110, the above-mentioned inks having the adjusted bleeding rate are used. On the other hand, black stored in the black ink cartridge 111
As the ink, a high-quality black image is used, and the ink bleeding rate is smaller than that of the color ink, and high-quality ink is used.

FIG. 2 shows the print head 102. Yellow, magenta, cyan, and black ejection port groups are arranged on the front surface of the print head 102 in a straight line. Each group has 24 discharge ports for yellow, magenta, and cyan, and 64 discharge ports for black, and the intervals between colors are equal to or greater than the nozzle pitch.

Each of these ejection ports is provided with an ink liquid passage communicating with the ejection port, and a common liquid for supplying ink to these liquid passages is provided behind the portion where the ink liquid passage is provided. A room is provided. The ink liquid path corresponding to each of the ejection ports is provided with an electrothermal converter that generates thermal energy used for ejecting ink droplets from these ejection ports and electrode wiring for supplying electric power to the electrothermal converter. ing. These electrothermal converters and electrode wirings are formed by a film forming technique on a 201 substrate made of silicon or the like. Further, the ejection port, the ink liquid passage, and the common liquid chamber are formed by stacking a partition wall made of a resin, a glass material, a top plate, etc. on the substrate. Further on the rear side, a drive circuit for driving the electrothermal converter based on a recording signal is provided in the form of a printed circuit board.

The silicon substrate and the printed circuit board 202 are the same aluminum plate 203 and the pipe 20 protruding in parallel.
Reference numerals 4 to 207 project from a plastic member 208 called a distributor that extends in a direction perpendicular to the silicon substrate, and further communicates with a flow path inside thereof.
The flow path communicates with the common liquid chamber.

There are four channels in the distributor for yellow, magenta, cyan and black.
Each common liquid chamber is connected to a pipe.

About 40 ng from the yellow, magenta, and cyan discharge ports provided on the print head 102.
Ink is about 80n from the black discharge port.
g of ink is ejected.

FIG. 3 is an electrical control block diagram of the color ink jet recording apparatus described above.

Reference numeral 301 denotes a system controller for controlling the entire apparatus, which has a storage element (RO) in which a control program including a microprocessor is stored.
M), a memory element (RAM) and the like used when the microprocessor performs processing are arranged. Reference numeral 302 denotes a driver for driving the print head in the main scanning direction,
Similarly, 303 is a driver for moving in the sub-scanning direction. Reference numerals 304 and 305 denote motors corresponding to the driver, which operate by receiving information such as speed and moving distance from the driver.

A host computer 306 is a device for transferring information to be printed to the printing device of the present invention. Reference numeral 307 denotes a reception buffer for temporarily storing data from the host computer, which stores data until the data is read from the system controller 301. A frame memory 308 expands data to be printed into image data, and has a memory size for printing. In this example, a frame memory capable of storing one print sheet will be described, but the present invention is not limited to the size of the frame memory.

Reference numeral 309 denotes a storage element for temporarily storing the data to be printed, and the storage capacity changes depending on the number of nozzles of the recording head. Reference numeral 310 denotes a print control unit for appropriately controlling the print head according to a command from the system controller, and a print control unit for controlling the ejection speed, the number of print data, and the like. 311 is 312Y, 312M,
A driver for driving the heads 312C and 312Bk, which is controlled by a signal from the print control unit 310.

FIG. 4 is a flow chart showing the operation of each embodiment of the present invention.

In STEP 1, the host computer 30
6, the data is transferred, and the system controller 301 reads the data stored in the reception buffer 307. In STEP 2, it is determined whether the read print data includes black data or only data other than black. When black is included, the process proceeds to STEP 7, and in other cases, the process proceeds to STEP 10.

At STEP 7, attention is paid to the black color data, and it is determined whether or not there is color print data in a pixel adjacent to the periphery of the black image print area. Here, the adjacent position is a position “upper and / or lower and / or left and / or right” with respect to each pixel forming the black image area on the recording medium, and a color image area is formed at this position. It is determined whether or not there is at least one color recording pixel to be processed. The pixel pitch P is about 70.56 μm, and the recording density is 360 dpi. If there is a color pixel adjacent to the black recording pixel, the process proceeds to STEP8, and if not, the process proceeds to STEP9.

At STEP 8, the black recording pixels are expanded in the C, M and Y data buffers for color recording. STE
At P9, the black recording pixels are expanded in the Bk data buffer for black recording. In STEP 10, each color data is expanded in each color data buffer. In STEP 11,
Data is read from the reception buffer, and it is determined whether there is data to be printed and whether one page of data has been received. As a result of the determination, if there is no print data, or if there is print data but one page of data has already been received, the process proceeds to STEP 12. STE otherwise
Return to P1. In STEP 12, the recording head 102 performs the recording operation.

FIG. 9 is an example showing an image in which a black image and a color image are mixed. The image portion A is composed of black characters of X, Y, Z and underlines, and is bit image data. The image portion B is code data of black characters. Image part C is an image with a black graph on the yellow background,
It is bit image data. The image portion D is an image having black character code data on the cyan background portion. Image part E
Shows the case where a magenta image is present in a part of the background for black bit image data.

According to the above method, the image area A is only black and has no background color, that is, for the black recording area,
Since the color recording areas are not in contact with each other, recording is performed by the black ink recording head that ejects (discharges) black ink. The image portion B is the same as the image portion A and is recorded by the black ink recording head. Since the image portion C and the image portion D are images of other colors around the black image, the black portion is recorded with color ink, that is, three color inks of Y, M, and C. The image part E is
Among the bit image data of black, the number "1" is recorded by the black recording head because the color image is not adjacent to it. On the other hand, the number "3" is printed by the color ink recording head because the surroundings are all adjacent to the magenta image. The number "2" is printed by the color ink recording head because a part of its periphery is adjacent to the magenta image.

As described above, when the black image recording area is independent and no other color is recorded in the surroundings, the Bk ink having a high recording density and less feathering is used, and the black image recording area is not independent. That is, when at least a part of the black image recording area and the image areas of other colors are in contact with or overlapping with each other, the black image recording area is recorded with the C ink, the M ink, and the Y ink to obtain black. Records a high-quality color image that prevents bleeding with other colors.

Further, the method for determining whether or not the color recording data exists in the pixel adjacent to the periphery of the black image recording area is processed by software here, but the method is not limited to this. , May be replaced with hardware for processing.

In the above example, it is determined whether or not another color is recorded around the entire black image recording area.
The calculation for making this determination requires a relatively long time for a recording method aiming at a higher-speed recording process, and thus has a heavy load. Therefore, as shown in FIG. 6, by performing the same processing only on the character code in the black image recording area, the calculation processing can be sped up.

In FIG. 6, STEP 3 is added as compared with the above example. In this STEP 3, if the black image recording area of interest is the character code, the subsequent processing is performed in the same manner as in FIG. 5, but if it is image data other than the character code such as bit image data, the process proceeds to STEP 8 and the black recording is performed. Pixels are developed in C, M, and Y data buffers for color recording.

Even with such processing, there is an advantage that at least the quality of black characters can be kept high.

Another example will be described. STE of FIG.
In P7, the position adjacent to the periphery of the black image recording area is the position “up and / or down and / or left and / or right” with respect to each pixel forming the black image area on the recording medium. did. This is an example in which the pitch P of the recording pixels is P or less, and it is necessary to widen this range depending on the ink used and the recording medium.

An experiment was conducted in which recording was performed on various types of plain paper using each ink of this example. Assuming that the range X of the black image recording area with respect to the pitch P of recording pixels, X = √
2, i.e. the position of "top and / or bottom and / or left and / or right and / or top right and / or top left and / or bottom right and / or top left" of the black pixel of interest was considered. Next, up to X = 2 was considered. Similarly, X = 2√
It was set to 2. In this way, the effect of the present invention was satisfactorily exhibited on most types of plain paper by performing the processing in consideration of X = 4√2.

From the above, the position adjacent to the periphery of the black image recording area of interest is defined as P for the minimum pixel pitch of recording for each pixel forming the black image area on the recording medium.
A case where at least one color recording pixel forming a color image area exists at a recording position within XP.
The case of 4√2 ≧ X ≧ 1 is effective for the present invention.

In the above-mentioned example, the case where the frame buffer for recording one page is provided is shown, but the present invention can be applied even when the line buffer is provided instead of the frame buffer.

This is done in step 7 of FIG. 4 as "positions adjacent to the periphery of the black image recording area" for each pixel forming the black image area on the recording medium. However, in addition to this, by assuming that the periphery of the black image recording area is not adjacent to other colors at least in the effective recording area of the line buffer, this problem is solved. Solve.

In the above description, a so-called bubble jet recording method is used as a recording head, in which bubbles are generated in the ink by an electrothermal converter and the ink is ejected by the action of the bubbles. Needless to say, the present invention can be applied to a so-called piezo inkjet recording system in which ink is ejected by the body.

Hereinafter, a more specific description will be given with reference to Examples and Comparative Examples. In the following description, parts and% are based on weight unless otherwise specified.

First, the following components were mixed and dissolved, and then pressure-filtered with a membrane filter having a pore size of 0.22 μm (trade name: Fluoropore filter, manufactured by Sumitomo Electric Co., Ltd.) to obtain yellow, magenta, cyan and black. Recording inks (1) to (10) were obtained.

[0072] (1) yellow   C. I. Direct Yellow 86 2nd copy   Lauryl alcohol ethylene oxide adduct 0.5 parts     (Additional mol number 10)   30 parts of diethylene glycol   67.5 parts water

[0073] Magenta   C. I. Assidred 35 3 parts   Lauryl alcohol ethylene oxide adduct 0.5 parts     (Additional mol number 10)   30 parts of diethylene glycol   Water 66.5 parts

[0074] cyan   C. I. Direct Blue 199 2nd copy   Lauryl alcohol ethylene oxide adduct 0.5 parts     (Additional mol number 10)   30 parts of diethylene glycol   67.5 parts water

[0075] black   C. I. Food Black 2 2 copies   Diethylene glycol 10 parts   88 parts of water

[0076] (2) yellow   C. I. Direct Yellow 86 2nd copy   Nonylphenol ethylene oxide adduct 5 parts     (Additional mole number 18)   Diethylene glycol 15 parts   78 parts of water

[0077] Magenta   C. I. Assidred 35 3 parts   Nonylphenol ethylene oxide adduct 5 parts     (Additional mole number 18)   Diethylene glycol 15 parts   Water 77

[0078] cyan   C. I. Direct Blue 199 2nd copy   Nonylphenol ethylene oxide adduct 5 parts     (Additional mole number 18)   Diethylene glycol 15 parts   78 parts of water

[0079] black   C. I. Food Black 2 2 copies   Diethylene glycol 10 parts   88 parts of water

[0080] (3) yellow   C. I. Direct Yellow 86 2nd copy   Ethylene oxide propylene oxide copolymer 3 parts     (Additional mole number 7)   Thiodiglycol 20 parts   75 parts of water

[0081] Magenta   C. I. Assidred 35 3 parts   Ethylene oxide propylene oxide copolymer 3 parts   (Additional mole number 7)   Thiodiglycol 20 parts   74 parts of water

[0082] cyan   C. I. Direct Blue 199 2nd copy   Ethylene oxide propylene oxide copolymer 3 parts   (Additional mole number 7)   Thiodiglycol 20 parts   75 parts of water

[0083] black   C. I. Food Black 2 2 copies   Thiodiglycol 15 parts   Water 83 parts

[0084] (4) yellow   C. I. Direct Yellow 86 2nd copy   Acetylene glycol ethylene oxide adduct 1 part   (Additional mol number 10)   Thiodiglycol 10 parts   Glycerin 10 parts   Water 77

[0085] Magenta   C. I. Assidred 35 3 parts   Acetylene glycol ethylene oxide adduct 1 part   (Additional mol number 10)   Thiodiglycol 10 parts   Glycerin 10 parts   76 parts of water

[0086] cyan   C. I. Direct Blue 199 2nd copy   Acetylene glycol ethylene oxide adduct 1 part   (Additional mol number 10)   Thiodiglycol 10 parts   Glycerin 10 parts   65 parts of water

[0087] black   C. I. Food Black 2 3rd Part   Thiodiglycol 5 parts   Glycerin 5 parts   5 parts of urea   Isopropyl alcohol 3 parts   79 parts of water

[0088] (5) yellow   C. I. Direct Yellow 86 2nd copy   Decaglycerin monolaurate 15 parts   30 parts of diethylene glycol   Water 50.2 parts

[0089] Magenta   C. I. 2 parts of Acid Red   Decaglycerin monolaurate 15 parts   30 parts of diethylene glycol   Water 50.2 parts

[0090] cyan   C. I. Direct Blue 199 2nd copy   Decaglycerin monolaurate 15 parts   30 parts of diethylene glycol   Water 50.2 parts

[0091] black   C. I. Food Black 2 2 copies   Decaglycerin monolaurate 0.2 parts   Diethylene glycol 12 parts   Water 85.8 parts

[0092] (6) yellow   C. I. Direct Yellow 86 2nd copy   Lauryl sulfate sodium salt 0.2 parts   Diethylene glycol 15 parts   Water 82.8 parts

[0093] Magenta   C. I. 2 parts of Acid Red   Lauryl sulfate sodium salt 0.2 parts   Diethylene glycol 15 parts   Water 82.8 parts

[0094] cyan   C. I. Direct Blue 199 2nd copy   Lauryl sulfate sodium salt 0.2 parts   Diethylene glycol 15 parts   Water 82.8 parts

[0095] black   C. I. Food Black 2 2 copies   Diethylene glycol 15 parts   Cyclohexanol 0.1 part   Water 82.9 parts

[0096] (7) yellow   C. I. Direct Yellow 86 2nd copy   Ethylene glycol methyl ether 15 parts   Diethylene glycol 15 parts   68 parts of water

[0097] Magenta   C. I. 2 parts of Acid Red   Ethylene glycol methyl ether 15 parts   Diethylene glycol 15 parts   Water 82.8 parts

[0098] cyan   C. I. Direct Blue 199 2nd copy   Ethylene glycol methyl ether 15 parts   Diethylene glycol 15 parts   Water 82.8 parts

[0099] black   C. I. Food Black 2 2 copies   Diethylene glycol 15 parts   Cyclohexanol 0.1 part   Water 82.9 parts

[0100] (8) yellow   C. I. Direct Yellow 86 2nd copy   Isopropyl alcohol 15 parts   Diethylene glycol 15 parts   68 parts of water

[0101] Magenta   C. I. 2 parts of Acid Red   Isopropyl alcohol 15 parts   Diethylene glycol 15 parts   Water 82.8 parts

[0102] cyan   C. I. Direct Blue 199 2nd copy   Isopropyl alcohol 15 parts   Diethylene glycol 15 parts   Water 82.8 parts

[0103] black   C. I. Food Black 2 2 copies   Diethylene glycol 15 parts   Cyclohexanol 1 part   82 parts of water

Comparative example (9) yellow   C. I. Direct Yellow 86 2nd copy   Diethylene glycol 15 parts   Water 83 parts

[0105] Magenta   C. I. 2 parts of Acid Red   Diethylene glycol 15 parts   Water 83 parts

[0106] cyan   C. I. Direct Blue 199 2nd copy   Diethylene glycol 15 parts   Water 83 parts

[0107] black   C. I. Food Black 2 2 copies   Diethylene glycol 15 parts   Ethylene oxide propylene oxide copolymer 3 parts   (Additional mole number 7)   80 parts of water

(10) yellow   C. I. Direct Yellow 86 2nd copy   Diethylene glycol 5 parts   Cyclohexanol 0.1 part   Water 92.9 parts

[0109] Magenta   C. I. 2 parts of Acid Red   Cyclohexanol 0.1 part   Diethylene glycol 5 parts   Water 92.9 parts

[0110] cyan   C. I. Direct Blue 199 2nd copy   Cyclohexanol 0.1 part   Diethylene glycol 5 parts   Water 92.9 parts

[0111] black   C. I. Food Black 2 2 copies   35 parts of diethylene glycol   Cyclohexanol 3 parts   60 parts of water

Next, using the obtained inks (1) to (10), recording was performed on high-quality paper, commercially available copy paper, and bond paper using the recording apparatus of FIG. 1 and the recording head of FIG. However, according to the operation flow of FIG. 4, a black image adjacent to a color image was recorded with three color inks of yellow, magenta, and cyan, and a black image without adjacent color images was recorded using black ink.

FIG. 6 shows the dot diameter of the black ink and the color ink of the obtained recorded matter and the bleeding rate obtained from the dot diameter.

The dots on the recorded matter of the obtained high-quality paper are captured by a CCD camera and image processing is performed,
The area of the dot was calculated and converted into a perfect circle to obtain the dot diameter, which was used as the dot diameter of the present invention (B in the formula (I)).

The diameter of the discharged ink droplet of the present invention (C in the formula (I)) was determined by the following formula.

V = (4/3) π (C / 2) × 10 ⁻³ V: Droplet volume ejected per pulse (pl)

FIG. 7 shows the fixing time of the black ink and the color ink of the obtained recorded matter. The fixing time is measured in 5 seconds, such as 5 seconds, 10 seconds, and 15 seconds after full solid printing (100% duty solid printing) of yellow, cyan, magenta, and black inks on commercially available high-quality paper. The print part was rubbed at intervals with a filter paper (trade name: No. 5C, manufactured by Toyo Sanshi Co., Ltd.), and the time when there was no stain due to rubbing was measured as the fixing time.

(Evaluation Method and Evaluation Criteria) (1) Bleeding A color sample in which different colors are adjacent to each other was printed, the state of bleeding was observed, and evaluation was made according to the following criteria. The evaluated colors are black, yellow, magenta, cyan, and two colors of yellow, magenta, and cyan are overlaid and mixed to make a total of 7 colors of red, green, and blue.
Although it is a color, the bleeding at the boundary between black and yellow, magenta, cyan, red, green and blue and the bleeding between colors were separately evaluated.

B: No bleeding is observed at the color boundary.

B: Some bleeding at the color boundary is recognized, but within the practical range.

X: Remarkable bleeding, not practical.

(2) Black Character Quality Black alphanumeric characters are recorded so as not to be adjacent to the color image, and after leaving for 1 hour, there is no irregular or irregular bleeding under the microscope, or the edges of the characters are not visible. The sharpness was observed and evaluated according to the following criteria.

◯: No irregular or irregular bleeding occurred, and the edge of the character was sharp.

Δ: Some irregular or irregular bleeding is recognized, but it is within the practical range.

X: Many irregular or irregular bleeding,
The edges of the letters are not sharp and cannot be put to practical use.

The evaluation results are shown in FIG.

FIG. 10A is a schematic view of another printer to which the ink jet recording method to which the present invention is applicable is applied. 1y is a recording head for yellow ink and 1m is a recording head.
Is a recording head for magenta ink, 1c is a recording head for cyan ink, 1k is a recording head for black ink, 2 is a carriage carrying the recording head, 3 is a flexible cable for sending an electric signal from the printer body to the recording head,
4 is a cap unit having recovery means, 5y, 5m,
Reference numerals 5c and 5k are cap members corresponding to the recording heads 1y, 1m, 1c, and 1k, 6 is a wiper blade made of a member such as rubber, and 7 is recording paper held opposite to the recording heads.

FIG. 10 (b) shows one of the four recording heads mounted on the printer. In the portion where the recording head faces the recording paper, 64 ejection ports 2 are provided.
It is formed with a density of 360 pieces per inch (360 dpi). Each of these ejection ports 10 is provided with an ink liquid passage communicating with the ejection port, and a common liquid chamber for supplying ink to these liquid passages is provided behind the portion where the ink liquid passage is arranged. It is provided. The ink liquid path corresponding to each of the ejection ports is provided with an electrothermal converter that generates thermal energy used to eject ink droplets from these ejection ports, and an electrode wiring for supplying electric power to the electrothermal converter. Has been.

The present invention brings excellent effects particularly in a recording head and a recording apparatus of a system utilizing thermal energy among ink jet recording systems.

Regarding its typical structure and principle, see, for example, US Pat. Nos. 4,723,129 and 4740.
What is done using the basic principles disclosed in 796 is preferred. This method is a so-called on-demand type,
Although it can be applied to any of the continuous type, in particular, in the case of the on-demand type, it can be applied to the sheet holding the liquid (ink) or the electrothermal converter arranged corresponding to the liquid path. By applying at least one drive signal corresponding to the recorded information and giving a rapid temperature rise exceeding nucleate boiling, heat energy is generated in the electrothermal converter, and film boiling is caused on the heat acting surface of the recording head. As a result, bubbles can be formed in the liquid (ink) in a one-to-one correspondence with this drive signal, which is effective. By the growth and contraction of the bubbles, liquid (ink) is ejected through the ejection opening,
Form at least one drop. It is more preferable to make this drive signal into a pulse shape, because the bubble growth and contraction are immediately and appropriately performed, so that the ejection of the liquid (ink) with excellent responsiveness can be achieved. As the pulse-shaped drive signal, U.S. Pat. Nos. 4,463,359 and 4,345 are used.
Those as described in the '262 patent are suitable. If the conditions described in US Pat. No. 4,313,124 of the invention relating to the rate of temperature rise on the heat acting surface are adopted, more excellent recording can be performed.

As the constitution of the recording head, in addition to the combination constitution of the ejection port, the liquid passage, and the electrothermal converter (the linear liquid passage or the right-angled liquid passage) as disclosed in the above-mentioned specifications, US Pat. No. 4,558,333, US Pat. No. 4,558,333, which discloses a configuration in which a heat acting portion is arranged in a bending region.
A configuration using the specification of No. 459600 is also included in the present invention. In addition, Japanese Patent Application Laid-Open No. 59-123670 discloses a configuration in which a common slit is used as a discharge portion of the electrothermal converter for a plurality of electrothermal converters, and an opening for absorbing a pressure wave of thermal energy. The present invention is also effective when the configuration corresponding to the discharge portion is based on Japanese Patent Application Laid-Open No. 59-138461.

[0132]

As described above, according to the present invention, in the case of recording an independent black image area which does not come into contact with the color image area, the density of the black image area is made high and the recording quality is excellent. At the same time, in other areas, excellent recording quality without ink bleeding between black and each color, that is, high-quality black recording and high-quality color recording can both be achieved.

[Brief description of drawings]

FIG. 1 is a perspective view of an inkjet recording apparatus to which the present invention can be applied.

FIG. 2 is a head mechanism diagram of an inkjet recording apparatus to which the present invention can be applied.

FIG. 3 is a block diagram of an inkjet recording apparatus control circuit to which the present invention is applicable.

FIG. 4 is a flowchart illustrating the operation of the embodiment.

FIG. 5 is a flowchart illustrating another operation of the embodiment.

FIG. 6 is a table showing bleeding rates of examples.

FIG. 7 is a table showing fixing times in the example.

FIG. 8 is a table showing evaluation results of examples.

FIG. 9 is an example of an image for explaining the present invention.

FIG. 10 is a perspective view showing another ink jet recording apparatus to which the present invention can be applied.

[Explanation of symbols]

102 print head 103 cartridge 110 color ink cartridge 111 black ink cartridge 301 system controller 302 carriage motor driver 303 paper feed motor driver 304 carriage motor 305 paper feed motor 306 host computer 307 reception buffer 308Y, 308M, 308C, 308Bk frame memory 309Y for each color , 309M, 309C, 309Bk data buffer 310 for each color print control unit 311 print driver 312Y, 312M, 312C, 312Bk print head for each color

─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Jun Aoki 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Mayumi Yamamoto 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (56) References JP-A-4-147866 (JP, A) JP-A-3-41171 (JP, A) JP-A-62-216750 (JP, A) JP-A-5-330086 (JP, A) A) (58) Fields surveyed (Int.Cl. ⁷ , DB name) H04N 1/23-1/31

Claims (16)

(57) [Claims] 1. A color ink jet recording method for forming a desired color image on a recording medium by ejecting black ink and a plurality of color inks different from the black ink onto the recording medium. The bleeding rate represented by the formula (I) is smaller than the bleeding rate of the color ink, and for at least one black recording pixel forming the black image area on the recording medium, the minimum pixel pitch of recording is P, Based on whether or not at least one color recording pixel forming a color image area exists at a recording position within X · P (4√2 ≧ X ≧ 1), a color is formed adjacent to the periphery of the black image area. It is determined whether or not an image area is present. As a result of the determination, if the periphery of the black image area is not adjacent to the color image area, the black image area is formed by the black ink, and the black image area is formed. A color ink jet recording method, wherein the black image area is formed by the color inks of the plurality of colors when at least a part of the periphery of the color image area is adjacent to the color image area. (I) A = B / C A: Bleeding rate B: Diameter of single dot formed on high-quality paper (μm) C: Diameter of ejected single ink droplet (μm) 2. The method according to claim 1, wherein X = 1.
The color inkjet recording method described. 3. The color ink jet recording method according to claim 1, wherein X = √2. 4. The method according to claim 1, wherein X = 2.
The color inkjet recording method described. 5. The color ink jet recording method according to claim 1, wherein X = 2√2. 6. The bleeding rate of black ink is in the range of 1.2 to 2.5, and the bleeding rate of color inks is 1.8 to 3.5.
2. The color ink jet recording method according to claim 1, wherein 7. The ink according to claim 6, wherein the ink contains at least one of a surfactant and a penetrating solvent.
The color inkjet recording method described. 8. The surfactant to be added to the ink is an ionic surfactant, a nonionic surfactant, an amphoteric surfactant, or a mixture of two or more thereof. 7. The color inkjet recording method according to 7. 9. The color inkjet recording method according to claim 8, wherein the surfactant added to the ink is a nonionic surfactant. 10. The surfactant added to the ink is at least selected from a higher alcohol ethylene oxide adduct, an alkylphenol ethylene oxide adduct, an ethylene oxide-propylene oxide copolymer, and an acetylene glycol ethylene oxide adduct. 10. The color ink jet recording method according to claim 9, wherein the color ink jet recording method includes one kind. 11. The penetrating solvent added to the ink is an ether, a lower alkyl ether of a polyhydric alcohol,
The color inkjet recording method according to claim 7, further comprising at least one selected from monohydric alcohols. 12. A color ink jet recording method for forming a desired color image on a recording medium by ejecting black ink and a plurality of color inks different from the black ink onto the recording medium. The bleeding rate represented by the formula (I) is smaller than the bleeding rate of the color ink, and only the character code data portion of the black image area has a color image area adjacent to the periphery of the black image area. If the result of the determination is that the periphery of the black image region is not adjacent to the color image region, the black image region is formed with the black ink and at least one of the periphery of the black image region is formed. When a part is adjacent to the color image area, the black image area is formed by the color inks of the plurality of colors, and the black image area such as bit image data is formed by the color inks of the plurality of colors. Color ink jet recording method, comprising Rukoto. (I) A = B / C A: Bleeding rate B: Diameter of single dot formed on high-quality paper (μm) C: Diameter of ejected single ink droplet (μm) 13. A color ink jet recording method for forming a desired color image on a recording medium by ejecting black ink and a plurality of color inks different from the black ink onto the recording medium. Only when the bleeding rate represented by the formula (I) is smaller than the bleeding rate of the color ink and the black image area is not out of the range stored in the memory, the black image area is surrounded by the black image area. It is determined whether or not there are adjacent color image areas, and as a result of the determination, when the periphery of the black image area is not adjacent to the color image area, the black image area is formed by the black ink, When at least a part of the periphery of the black image area is adjacent to the color image area, the black image area is formed by the color inks of the plurality of colors, and the other black image areas are formed by the color inks of the plurality of colors. Color ink jet recording method, comprising Rukoto. (I) A = B / C A: Bleeding rate B: Diameter of single dot formed on high-quality paper (μm) C: Diameter of ejected single ink droplet (μm) 14. The color ink jet recording method according to claim 1, wherein the color inks of a plurality of colors are inks of yellow, magenta, cyan, or green, red, and blue colors. 15. The color ink jet recording method according to claim 1, wherein the fixing time of the black ink is longer than the fixing time of the color ink. 16. The color inkjet recording method according to claim 1, wherein the ink is ejected by thermal energy.